Polyculture trials - Polyculture vs Block Planting

We've completed the second year of our Market Garden Polyculture Study with some interesting results. This year we added a new polyculture to the trials and included a comparison between growing vegetables in a polyculture and growing them in more traditional blocks.

Below you will find an overview of the trial garden and the polycultures we are growing, a description of what we record and the results from this year's study.

First of all we'd like to say a huge thank you to the team of volunteers that joined us for the study this year and that make it possible for us to carry out our experiments and research. It was a pleasure to work together with you

The beds are named after common vegetable families in order to familiarize participants with the use of Latin and introduce them to some major plants families. They do not correspond to what was planted in the beds.

The Polycultures

We are experimenting with many polycultures and have developed a categorization system for ease of reference. They are categorized by life cycle i.e annual, perennial or combi (annuals and perennials) and further categorized by function. i.e support, infrastructure or production. Often a polyculture will provide multiple functions, but the primary function is what sets them to each category. I give all the polycultures nicknames. For example, all polycultures in the annual and production category are named after Stoic Philosophers.

The study is based on polycultures Zeno and Epictetus - both are annual and production polycultures. As we are looking to see how polycultures compare to conventional growing, this year we included a control for the Zeno polyculture i.e, the same crops from Zeno but planted in a more conventional block pattern. In the below illustration you can see the planting plan of the trial beds.

Polyculture Zeno

We've been growing Zeno in the garden for around 9 years now. It's been very successful in our home gardens and in 2015 we scaled it up for the market garden. You can see last year's market garden results here and three years of records from the home garden here.

Photos from Zeno Polyculture
For more info on plant spacing, management and maintenance of this polyculture see our previous post here.

Zeno Plant List - The following plants and cultivars were used in this polyculture;

We also included a control this year. The control included all of the above plants but planted in blocks along the bed (see below). We wanted to see how the two planting schemes compared i.e. whether the polyculture would produce more and the difference in the amount of time needed to cultivate them. The fertility inputs for both beds were the same.

Polyculture Epictetus

This is the first year we have tried this polyculture. It's basically a strip pattern of various vegetables from different plant families arranged to reduce pests and diseases, optimize space and nutrient share whilst respecting the individual plant needs for space and light.

Epictetus Polyculture

Epictetus Plant List - The following plants and cultivars were used in this polyculture;

The table below shows the floral species composition of each of the beds including the different cultivars and the dates that the plants were sown or planted.

We have not included a list of native wild plants that are encouraged to grow around the perimeter of each bed that we mow and apply as mulch to the beds during the growing season.

What we Record - Inputs

Time Input - We record how long it takes to develop, maintain and manage the garden. The time is recorded for each task starting from sowing the seeds, preparing the beds, planting and caring for the plants, harvesting, preparing for market and packing away. The time taken for each task is rounded up or down to nearest minute. Nearly all of the records are based on 2 people carrying out each task unless otherwise stated in the record sheet.

Financial Inputs - Costs - The costs associated with the garden are recorded. We do not cost the time spent on the garden but do provide the precise time the activities take. Set up and tool costs were included in the first year records. This year we only recorded operating costs.

N.B. We eliminate many costs by growing our own plants from seed, making composts and sowing mediums, growing summer and autumn mulch and saving seeds. We also provide our own support materials for the crops.

Basil seeds in the nursery room

What we Record - Outputs

Crop Yields - All produce is weighed directly after harvest. The produce is recorded into two categories, fit for market and fit for processing/fodder.

Polycultures Yields

Financial output - Profit - The market value of the produce is estimated based on the average prices we were receiving from local buyers, veggie boxes and Trustika buyers club in Sofia.

N.B. We do not sell all of the produce from the garden. Some of the produce is consumed by the team or preserved.

What we Record - Surveys

Soil Analysis - Each spring and autumn we obtain a soil sample and send it to NAAS of the Ministry of Agriculture and Food. To take a sample we take approx a hand trial full of the top 20 cm of soil from 8 random areas from the beds, mix it together and send 400g "bagged and tagged" to the lab the same day.

Physical Analysis - Each spring the team carry out a series of 9 tests that are designed to provide an indication of soil health based on observable physical properties of the soil. It's a soil management tool developed by farmers for farmers to track the developing health of soils. You can download the form with instructions how to carry out the tests here. We have slightly modified the test for our purposes.

Invertebrate Survey - We made a start on the invertebrate survey but have incomplete records and are not entirely happy with the method, so we will try again this coming year. We are looking for entomology enthusiasts to help us with this part of the study. If this interests you please get in touch for further discussion.

Support Species Tagetes spp. and Calendula officinalis are planted within the vegetables and attract a large diversity of invertebrates some of which are beneficial to the crops.

Results

We'll start off by looking at the results from the soil analysis and soil health tests, then look at the results for each polyculture and finally finish up with the overall garden results.

Soil Results - Mineral Analysis

Each spring and autumn we take soil samples and send them to NAAS of the Ministry of Agriculture and Food. The March sample is taken before we add any fertility and the November sample is taken after all of the crops have stopped producing.

The first sample taken in March 2015 in the table below is the base sample taken before work in the garden began.

Some time categories were difficult to assign to each polyculture so I clumped them together into a general task category. It's mainly the time preparing the produce for market as well as soil analysis, initial propagation tasks and end of season tidying up and packing away of the garden.

It's only the first year we have tried this comparative study so it's too early for any clear implications, but this year's result shows the polyculture out performing the control in terms of yields and the control taking less time to operate in. The fertility inputs were the same for each.

You can find the above results in the spreadsheet 2016 Annual Polyculture Market Garden Study - Published Records - Sheet 9. Inputs and Outputs per Trial. For date stamped harvest records for Zeno see here and for Epictetus see here.

The garden expenses were 115.56 BGN and the estimated value of the produce was 1911.46 BGN providing a profit of 1795.9 BGN. This translates to 12.05 BGN per hr or 10.84 BGN per m2.

Comments on Results

Time Input
Not included in the records were other tasks carried out around the site such as making compost, harvesting stakes and support sticks, establishing beneficial habitat such as wildlife ponds, hedgerows/stick piles.
The time for preparing the produce for market i.e quality control, packaging and delivery, was estimated at 2 hrs per week . We send out weekly veggie boxes and orders from a food coop with produce from our other gardens and did not record separately the polyculture trials produce.
Financial Inputs - Costs
Not included here are the set up costs for the garden. These costs were included in last years results. The costs recorded here are the annual operating costs.
Financial Output - Income
A polyculture market garden should be a polyculture of revenue streams. Our study currently focuses on annual vegetable production. We chose to begin our study of annual vegetables as it is the most accessible practice to most people requiring the least amount of investment making it ideal for a novice or curious grower. Other potential revenue from the Polyculture Market Garden includes perennial crops (see here for a perennial polyculuture study we are starting next year), plant nursery, adding value to produce and courses and training. We hope to add a study of these activities over time to represent better the financial potential of a Polyculture Market Garden.

Design of our new perennial polyculture garden coming in Spring 2017

Entomology Survey - We did begin to record invertebrate diversity in the beds and here you can find a photo album of what was recorded along with some other wildlife that resides in the garden. Thanks to Peter Alfrey for the photo records and survey.

Dylan and Ute in spring sweeping the native plants that grow around the edges of the beds.

Crop failure :-

Aubergines were also included in the Epictetus polyculture and failed to produce any significant yield.
A cold and wet April and May meant that many squash and beans did not germinate. This resulted in less production from beans and squash than would be expected. Next year we will be growing these plants in starter trays under cover and planting out when the weather conditions are favourable.

N.B. The majority of the tasks were carried out by a volunteer team that had little or no prior experience in horticulture. An experienced grower or with repeated experience of these cultivation methods should be able to reduce the task times significantly.

You can access the full spreadsheet here that includes all of the data entries and task descriptions. (note there are multiple sheets that can be accessed from the blue tabs running along the top of the sheet).

Why are we doing this research?

If you are reading this you're most probably aware of the environmental damage caused by industrial agricultural practices We believe this damage is unnecessary, and aim to provide healthier models of agriculture that yield nutritious affordable food while at the same time promoting biodiversity and general ecosystem health.

Polyculture gardens providing food for humans and other organisms

Industrial methods are heavily researched and funded, and there is a general belief among many farmers and growers that this is the only practical way of operating. Following 12 years of cultivating polyculture gardens we are seeing that small scale biologically cultivated polyculture gardens are a realistic and practical way of providing food for humans whilst preserving biodiversity and general health in the environment. Furthermore we believe this type of agriculture can help create thriving local economies that strengthen community, provide dignified work and enhance the amenity value of an area.

Little data exists showing the productive capacity of polyculture systems and the economic viability of them. There is a big need to fill this gap and provide solid data and concise coherent models that can be replicated easily and provide real solutions to the environmental damage caused by industrial agriculture. This project intends to go some of the way in filling this gap.

We aim to address the following questions;
How productive can polycultures be?
What advantages can polycultures provide ?
How much time do polyculture gardens take to establish and manage?
How economically viable are these gardens?
How bio-diverse can our food producing systems be?
Can we provide clean, nutritious, affordable food whilst enhancing biodiversity?

Want to get involved? Sharing, Feedback and Collaboration

We have our record keeping spreadsheets on Google Drive. These spreadsheets (see here) include all of the data entries and task descriptions (note there are multiple sheets that can be accessed from the blue tabs running along the top of the sheet). If you would like to keep your own records we'd be happy to give you a copy of the spreadsheet, just drop us an email or leave a comment below with your contact details and we will send it over to you.

If you have any suggestions and feedback on how you think we could improve the study or you have heard about or practice similar studies on other guild/polycultures we'd love to hear from you.

Next Year's Study

We're looking for a team of volunteers for 2017. If you'd like to join us have a read through the process here, register and we'll get straight back to you.